title: Experimental investigation and modeling of dissolved organic carbon removal by coagulation from seawater.
abstract: Coagulation removes colloidal matters and dissolved organic carbon (DOC) which can cause irreversible membrane fouling. However, how DOC is removed by coagulant is not well-known. Jar test was used to study the removal of hydrophobic and hydrophilic DOC fractions at various doses (0.5-8.0 mg-Fe(+3) L(-1)) of ferric chloride (FeCl3) and pH (5.0-9.0). Natural organic matter (NOM) in seawater and treated seawater were fractionated by liquid chromatography-organic carbon detector (LC-OCD). Compared to surface water, the removal of DOC in seawater by coagulation was remarkably different. Majority of DOC could be easily removed with very low coagulant dose (<5.0 mg-Fe(+3) L(-1)) and the removal efficiency did not vary with pH, but the DOC composition in treated water had significantly changed. Hydrophobic fraction (HB) was better removed at high pH while hydrophilic fraction (HF) was better removed at low pH. A modified model of Kastl et al. (2004) which assumed that the removal occurred by adsorption of un-dissociated compounds onto ferric hydroxide was formulated and successfully validated against the jar test data.
authors.affiliation: Faculty of Engineering and IT, University of Technology, Sydney (UTS), PO Box 123, Broadway, NSW 2007, Australia.
authors.forename: Sanghyun
authors.initials: S
authors.lastname: Jeong
authors.forename: Arumugam
authors.initials: A
authors.lastname: Sathasivan
authors.forename: George
authors.initials: G
authors.lastname: Kastl
authors.forename: Wang Geun
authors.initials: WG
authors.lastname: Shim
authors.forename: Saravanamuthu
authors.initials: S
authors.lastname: Vigneswaran
mesh_terms: D000327:Adsorption; D002244:Carbon / Q000737:chemistry*; D002712:Chlorides / Q000737:chemistry; D005290:Ferric Compounds / Q000737:chemistry; D008956:Models, Chemical; D012623:Seawater / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*
chemical_list: D002712:Chlorides; D005290:Ferric Compounds; C021024:ferric hydroxide; D002244:Carbon; C024555:ferric chloride
keywords: CDOC; Coagulation; DOC; Dissolved organic carbon; Ferric chloride; HB; HF; LC-OCD; LMW; Modeling; NOM; RO; Seawater; chromatographic DOC; dissolved organic carbon; hydrophilic; hydrophobic; liquid chromatography-organic carbon detector; low molecular weight; natural organic matter; reverse osmosis